Acute and chronic diarrheas represent a major medical problem in many areas of the world. Diarrhea is both a significant factor in malnutrition and the leading cause of death (5,000,000 deaths/year) in children less than five years old. Secretory diarrheas are also a dangerous condition in patients of acquired immunodeficiency syndrome (AIDS) and chronic inflammatory bowel disease (IBD). 16 million travelers to developing countries from industrialized nations every year develop diarrhea, with the severity and number of cases of diarrhea varying depending on the country and area of travel. The major medical consequences of diarrheal diseases include dehydration, acidosis, death and impaired growth.
Diarrhea in barn animals and pets such as cows, pigs and horses, sheep, goats, cats and dogs, also known as scours, is a major cause of death in these animals. Diarrhea can result from any major transition, such as weaning or physical movement. One form of diarrhea is characterized by diarrhea in response to a bacterial or viral infection and generally occurs within the first few hours of the animal's life.
Although the major consequences of diarrheal diseases are very similar, there are numerous causes of diarrhea. Secretory and exudative diarrhea are primarily caused by bacterial or viral infections. The most common diarrheal causing bacteria is enterotoxogenic E-coli (ETEC) having the K99 pilus antigen. Common viral causes of diarrhea include rotavirus and coronavirus. Other infectious agents include cryptosporidium, giardia lamblia, and salmonella, among others.
The treatment for diarrhea depends on the patient and the infection source. Diarrhea which is found in travelers to industrialized nations (travelers diarrhea) frequently is caused by bacterial pathogens which are acquired through ingestion of fecally contaminated food and/or water. Approximately 50-75% of these cases are attributed to ETEC. Although traveler's diarrhea is painful, it is generally not life-threatening and often the symptoms last only 3-5 days. The symptoms include urgent diarrhea, abdominal cramps, nausea and fever. The most effective course of treatment for traveler's diarrhea is the administration of antibiotics in conjunction with oral rehydration. It has been shown that prophylactic administration of antibiotics drastically reduces the number of travelers experiencing symptoms of diarrhea. However, routine administration of antibiotics is not suggested as it may cause resistant strains of a bacteria to develop. Other treatment methods include administration of bismuth subsalicylate, often taken in the form of Pepto-Bismal, diphenoxylate and loperamide.
Diarrhea in AIDS patients is a very serious condition which causes wasting and may be an important factor in the decline of these patients. AIDS patients often develop diarrhea due to enteric infections which their immune system is not capable of fighting off, but AIDS patients may also develop diarrhea by AIDS enteropathy. AIDS enteropathy is a disorder characterized by diarrhea without the involvement of secondary infections. It is caused by the human immunodeficiency virus (HIV) infection of the small bowel mucosal cells and colonic mucosal cells. The most common infective agent causing diarrhea due to enteric infection in AIDS patients in cryptosporidium. The methods for treating diarrhea in AIDS patients include administration of antibiotics and administration of immunoglobulins or an immunoglobulin enriched fraction of bovine colostrum. Colostrum, which is the first milk produced by mammals after birthing is enriched with antibodies.
Acute diarrhea or scours, is a main cause of death in many newborn barn animals such as calves and pigs. Scours is often caused by ETEC with a K99 pilus antigen. Infection with the ETEC causes hypersecretion of fluid and electrolytes. Hypersecretion in turn causes dehydration and pH imbalance which may result in death of the newborn calf or pig.
Newborn barn animals are also susceptible to viral infectious agents causing scours. Infections with rotavirus and coronavirus are common in newborn calves and pigs. Rotavirus infection often occurs within 12 hours of birth. Symptoms of rotaviral infection include excretion of watery feces, dehydration and weakness. Coronavirus which causes a more severe illness in the newborn animals, has a higher mortality rate than rotaviral infection. Often, however, a young animal may be infected with more than one virus or with a combination of viral and bacterial microorganisms at one time. This dramatically increases the severity of the disease.
Generally the best protection for a newborn barn animal from viral or bacterial infection is the consumption of colostrum. If the mother animal has been exposed to these infectious agents then the colostrum will contain antibodies, which are often sufficient to protect the newborn from contracting the diseases. Sometimes, however, this is not sufficient and the animals need further protection. A common method of treatment includes administration of a concentrated colostrum solution or an immunoglobulin fraction isolated from a colostrum solution. This oral treatment may be combined with rehydration salts. Although these methods have improved the morbidity and mortality rate of newborn animals having scours, there still exists a need for more effective treatments.
Certain imidazoles such as clotrimazole are agents which have been used both topically and systemically as antifungals. More recently, studies have identified other uses for such imidazoles. U.S. Pat. No. 5,273,992 revealed that these imidazoles regulate Ca.sup.++ actuated K.sup.+- channels in erythrocytes, and are thus useful in treating sickle cell anemia, which involves the inhibition of potassium transport. These imidazoles have also been found to be effective in inhibiting endothelial and/or vascular smooth muscle cell proliferation. The results of this finding are described in U.S. Pat. No. 5,358,959 and U.S. Ser. No. 08/018,840, which discloses using clotrimazole for treating atherosclerotic and angiogenic conditions, respectively. Nonimidazole metabolites and analogs of the foregoing compounds also have been described as useful in treating the foregoing conditions (see U.S. Ser. Nos. 08/307,874 and 08/307,887).